1. Field of the Invention
The present invention relates to electromagnetic relays of the type having an insulating support structure for a coil including a yoke which together operate an angular armature adapted to pivot on an end of the yoke, and it relates, more particularly, to a retaining spring adapted to retain both the armature and the yoke (or frame) while positioning the armature against an edge surface of the armature serving as a fulcrum to operate an associated contact assembly.
2. Description of Prior Art
Various electromagnetic relays and configurations are known to those in the art and used wherein the coil including a yoke and an armature as well as a contact assembly are mounted on a common base or support structure. Typically, the support structure includes protruding walls for supporting the yoke and also provides insulative protection between the coil and the contact assembly.
For example, U.S. Pat. No. 4,429,292 discloses an electromagnetic relay having an insulating support structure with sidewalls and longitudinal grooves provided in the sidewalls for inserting and fastening a leg of the yoke. A retaining plate located between the yoke leg and the coil is supported against the yoke leg and has a pair of bent lateral flanges engaged in the grooves. For initial mounting of the retaining plate on the yoke, lateral fastening brackets are located on the plate for engaging plug projections that serve as lateral snap-in teeth on the yoke leg, thus presenting a rather complicated spring form and mounting procedure. In addition, a separate retainer spring is needed for pressing the armature against the yoke or a further structural addition is required in the spring form to serve as a separator plate between the armature of the relay and the yoke.
In U.S. Pat. No. 3,406,361 another relay configuration is disclosed which features a one-piece spring clip that is generally U-shaped for fastening the yoke to the relay base. However, this conventional U-shaped spring-frame embraces the coil from both sides and is quite large in size. Further, conventional springs in this form may present insulation problems. In addition in relays where the axis of the coil is perpendicular to the base, a U-shaped retainer clip is not easy to fasten on to the yoke leg which is also perpendicular to the base. Thus, such a conventional relay configuration leads to assembly difficulties.